diff --git a/lib/src/enums.dart b/lib/src/enums.dart
index 922b8ba..9756b30 100644
--- a/lib/src/enums.dart
+++ b/lib/src/enums.dart
@@ -7,7 +7,6 @@ enum UnitType {
 }
 
 enum Difficulty {
-  notSelected,
   veryEasy,
   easy,
   intermediate,